Figure 4.

3D reconstructions from SBF-SEM volumetric data reveals plicae morphology (A) Serial block face image showing a portion of an ICD with two folds contoured in yellow and green, and the nexus in blue. The arrow indicates the tip of the green fold. Scale bar = 500 nm. (B) Corresponding portion of the 3D ICD volume illustrates how the fold segmented in yellow does not correspond to the height/amplitude of the finger-like projection but to an oblique cross section and contributes to two projections (labelled 1 and 2). Similarly, the single green fold in (A) contributes toward three individual finger-projections in 3D (labeled a, b, and c). (C) Measurement of the height (amplitude) of the plicae by connecting the tips and the troughs of the finger-like projections to define the surface topology (between 50 and 500 individual measurements made per plicate domain) three plicate domains within a single ICD are shown. Plicate I; upper and lower surfaces are colored green and purple, plicate II; red and dark blue, plicate III; red and light blue. The lines between the two sheets indicate the individual height measurements taken in 3D. Scale bar = 500 nm. (D) The base diameter of the finger-like projections (indicated by the double-headed arrow) was also measured (1123 individual folds analyzed). A section of the ICD has been clipped and the surface capped with a blue mesh to illustrate this dimension. Scale bar = 500 nm. To see this figure in color, go online.